【Abstract】 Objective To compare EPO and CEPO's influence on hemorheology of pregnant rats. Method Fifteen 17day pregnant rats were randomly divide into NS Group (n=5), EPO Group (n=5) and CEPO Group (n=5). Pregnant rats were injected 09% NS (1mL once a day i.p.), EPO (5,000 U/Kg once a day i.p.) and CEPO (50 μg/Kg once a day i.p.) respectively for three consecutive days. The related parameters of blood routine and hemorheology of pregnant rats were detected at 4th day. And parameters were evaluated using Pearson's correlation coefficient. Results RET#, RET%, HFR, IRF, RBC and HGB in EPO Group were higher than those in NS Group and CEPO Group (P＜005). Blood viscosity of shear rate 1, shear rate 5 and HCT in EPO Group were higher than those in NS Group and CEPO Group (P＜005). Blood viscosity of shear rate 1 and 5 were positively correlated with erythrocyte aggregation index. HCT is positively related to RBC, HGB and RET#. Conclusions EPO is able to induce hematopoiesis bioactivity of bone marrow, cause an increase in HGB, blood viscosity of low shear rate and HCT, and cause changes in hemorheology in pregnant rats. However, CEPO does not have these functions. It is revealed that CEPO is more suitable for obstetric applications than EPO.